Alternative Electronics

This page has been flagged as containing duplicate material that "Official" Electronics also attempts to cover.These pages should be merged such that both pages do not attempt to cover the duplicate topics.

THIS page is an extremely rough draft. You can help us improve it.
(Someday this page will document many of the known-working systems. A few known-working systems are already documented at RepRap Options).

Endstops

Extruder Controller

Overview

The page RepRapElectronics has a good high-level description of what the electronics do and how they connect to the rest of the system.
The standard, well-tested RepRap electronics are described at circuit board construction.
Various ways of mounting and cooling RepRap electronics (whether standard or nonstandard) are described at Electronics Improvements.

Many people have come up with ideas for improving on those electronics.
We list and compare and contrast some of those ideas here.

MakeIDCCable -- the cables used in many (most? all?) RepRaps and RepStraps.

4 Axis TB6560 CNC Stepper Motor Driver Board Controller -- 4 Axis TB6560 CNC Stepper Motor Driver Board Controller (4+1 channel CNC board ment to be used from parallel port but can be easily used from mcu. Includes opto insulation, 4 stepper channels and 1 relay. Includes large heat sink and is capable of running steppers up to 24V, 3A)

DIY Circuit Board Manufacturing

According to some estimates, the vast majority of RepRap and RepStrap machines use one of the above custom PCBs specifically designed for RepRap and fabbed by a commercial PCB fabricator. Mendel Buyers Guide and PartsSupplies lists some of the places selling such PCBs, either the empty PCB or the assembled PCBA with all the parts already soldered on.

Goals

See Development Pathway for goals and ideas for improving RepRap in general.
Here, we focus ideas for improving the electronics alone.

There are a variety of ways of "improving" the RepRap electronics -- but, alas, several of these ways conflict with each other:

reduce the net cost of all the motors and electronics and connectors, when fabricated and assembled at commercial PCB fab and board assembly house in high volumes. This seems to imply putting everything on one board, eliminating the cost of connectors between boards; eliminating parts that are not absolutely essential to run a single RepRap with a single extruder; and using tiny narrow-pitch surface-mount components packed tightly together, to reduce the size and therefore cost of the PCB.

add one or more features that early RepRap electronics doesn't have

SD card reader and LCD screen so that it can run "stand-alone" disconnected from any PC host.

make it possible for people to fab the boards with a relatively crude homebrew process -- perhaps one of the Automated Circuitry Making techniques. This implies spacing parts relatively far apart to leave more room for the relatively wide isolation gaps and wide traces these techniques produce.

As far as possible, use only widely-available parts that are unlikely to go obsolete soon -- available from multiple manufacturers, etc.

Lots of flexibility to allow a variety of "functional units" to be substituted. Then the assembler can use whatever is cheapest at the time and location. Easy to switch to alternate parts if the original parts are unavailable. Easy to experiment by temporarily swapping in a new functional unit to test if it is really better than the old unit. Easy to upgrade just one functional unit if a better unit becomes available -- less buggy, more fault-tolerant, faster, more power-efficient, etc.

make it possible for people to assemble all the parts on the boards with relatively crude soldering tools -- this implies easy-to-solder parts, either through-hole parts or large wide-pitch surface-mount parts.

Perhaps the biggest philosophical conflict between RepRap PCB designers is between people who are aiming in two very different directions:

A completely stand-alone RepRap. A person turns on the RepRap, presses buttons on the RepRap to select "measuring cup" on its small LCD panel, and then the RepRap prints out a measuring cup. Since there is no PC hooked to it, all computation is done internally with a medium-cost processor, and all status shows up on the LCD panel and a few dozen blinking LEDs.

A "3D printer" as a dedicated computer peripheral. A person designs a new measuring cup on a full-size computer running his favorite operating system and his favorite 3D CAD software, hits "print", and then the RepRap prints out a measuring cup. Since it's hooked up to a PC with a (relatively) fast processor and (relatively) huge display screen, it offloads as much computation and status display as possible to the PC. The internal low-cost processor handles the remaining real-time tasks that cannot be done by the PC.